The present invention relates to new methods for making subphthalocyanine compounds. The present invention also relates to a family of new subphthalocyanine compounds. The new subphthalocyanine compounds may be used as a colorant, alone or in combination with one or more colorants. The present invention further relates to inks containing the new subphthalocyanine compounds.
A variety of subphthalocyanine compounds and methods for making the same are known in the art. Most conventional methods for producing subphthalocyanine compounds typically require a high reaction temperature, usually in the range of about 200xc2x0 C. to about 250xc2x0 C., due to the use of solvents, such as 1-chloro-naphthalene. Further, most conventional methods produce subphthalocyanine compounds along with a variety of secondary products, which require extensive separation procedures in order to isolate the subphthalocyanine compound. In addition, the reaction yield for the production of subphthalocyanine compounds by most conventional methods is at most about 35%, and usually less than about 20%. Such reaction conditions result in high energy costs, potential damage to the environment due to environmentally-unfriendly solvents, and low yields, which in turn results in high costs for the subphthalocyanine compounds produced.
U.S. Pat. No. 5,864,044 issued to Van Lier et al. discloses methods of making subphthalocyanine compounds, wherein a solvent having a lower boiling point is used. Van Lier discloses the use of 1-chlorobenzene (b.p. 130xc2x0 C.) as a suitable solvent for the production of subphthalocyanine compounds. However, 1-chlorobenzene is an environmentally unfriendly solvent currently under increased scrutiny by the U.S. Environmental Protection Agency. Although Van Lier discloses the production of subphthalocyanine compounds at yields of about 60%, the method uses an environmentally unfriendly solvent, which presents manufacturing problems in the U.S.
Although the prior art discloses methods of making subphthalocyanine compounds at yields of up to about 60%, higher yields are desired in order to cost-effectively produce subphthalocyanine compounds. Further, higher yields without the use of environmentally unfriendly solvents are more desirable.
Moreover, known subphthalocyanine compounds possess poor lightfastness properties, which prevent the compounds from being used as colorants in conventional ink sets. It is believed that the poor lightfastness of known subphthalocyanine compounds is primarily due to the high reactivity of the molecule in the excited state, as well as, the higher concentration of molecules in the excited state and the length of time in the excited state, when a sample of the molecule is exposed to light. As reported in xe2x80x9cSynthesis and Nonlinear Optical, Photophysical, and Electrochemical Properties of Subphthalocyaninesxe2x80x9d, del Rey et al., J. Am. Chem. Soc., Vol. 120, No. 49 (1998), known subphthalocyanine compounds have an excited state lifetime of as much as 100 xcexcsec. Other possible reasons for poor lightfastness and tendency to fade are (1) reaction with singlet oxygen, and (2) nucleophilic attack resulting in a loss of boron and/or substitution of a chromophore.
What is needed in the art is an improved method of making subphthalocyanine compounds, which uses an environmentally-friendly solvent, and at the same time, results in yields of greater than 50%. Further, what is also needed in the art is a new family of stable, subphthalocyanine compounds having improved lightfastness properties, which may be used as colorants, alone or in combination with one or more colorants.
The present invention addresses the needs described above by providing new methods of making subphthalocyanine compounds. The methods of the present invention may be used to produce known subphthalocyanine compounds, as well as, new families of subphthalocyanine compounds having superior light fastness properties disclosed herein.
The present invention is further directed to a new family of subphthalocyanine compounds having the following general formula: 
wherein X1 to X12 each independently represent carbon or nitrogen; R1 to R12 and Z each independently represent xe2x80x94H, a halogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxide group, a phenoxy group, a substituted phenoxy group, an alkyl sulfide, an aryl sulfide, a nitrogen-containing group, a sulfonic acid, a sulfur-containing group or an ester group; and wherein when any one of X1 to X12 is nitrogen, the corresponding R1 to R12 represents the pair of electrons on the nitrogen atom. The subphthalocyanine compounds may be used as a colorant alone or in combination with one or more colorants.
The present invention also relates to colorant compositions having improved stability, wherein the colorant comprises one or more of the above-described subphthalocyanine compounds.
These and other features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiments and the appended claims.
The present invention is directed to methods of making subphthalocyanine compounds. The methods of the present invention may be used to produce known subphthalocyanine compounds, as well as, a new family of subphthalocyanine compounds disclosed herein. Unlike conventional methods of making subphthalocyanine compounds, the methods of the present invention utilize a reaction mechanism, which occurs at a temperature below about 180xc2x0 C., while employing environmentally friendly solvents. In addition, the methods of the present invention produce subphthalocyanine compounds at a reaction yield of greater than about 50%, and up to about 94%.
One method of making subphthalocyanine compounds of the present invention may be given by the following reaction scheme: 
wherein X1 to X12 each independently represent carbon or nitrogen; R1 to R12 and Z each independently represent xe2x80x94H, a halogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxide group, a phenoxy group, a substituted phenoxy group, an alkyl sulfide, an aryl sulfide, a nitrogen-containing group, a sulfonic acid, a sulfur-containing group, or an ester group; and wherein when any one of X1 to X12 is nitrogen, the corresponding R1 to R12 represents the pair of electrons on the nitrogen atom. The reaction may occur at a reaction temperature much lower than most conventional reaction methods. In one embodiment of the present invention, the method of making subphthalocyanine compounds takes place at a desired reaction temperature of from about 20xc2x0 C. to about 180xc2x0 C. More desirably, the reaction temperature is from about 50xc2x0 C. to about 160xc2x0 C. Even more desirably, the reaction temperature is from about 80xc2x0 C. to about 150xc2x0 C.
In a further embodiment of the present invention, the method of making subphthalocyanine compounds may be given by the following reaction scheme: 
wherein R1 to R4, R7 to R12 and Z each independently represent xe2x80x94H, a halogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxide group, a phenoxy group, a substituted phenoxy group, an alkyl sulfide, an aryl sulfide, a nitrogen-containing group, a sulfonic acid, a sulfur-containing group, or an ester group. The reaction may occur at a reaction temperature as discussed above, with the desired reaction temperature being from about 80xc2x0 C. to about 150xc2x0 C. The resulting subphthalocyanine compounds have a unique, unsymmetrical chemical structure, which enables xe2x80x9cintramacrocyclic quenching,xe2x80x9d as well as, xe2x80x9cintermacrocyclic quenchingxe2x80x9d with other molecules as described below.
The methods of the present invention use a variety of environmentally-friendly solvents. Desirably, the solvent comprises a xe2x80x9chydrogen-donatingxe2x80x9d solvent. As used herein, the term xe2x80x9chydrogen-donatingxe2x80x9d describes solvents, which are capable of donating a hydrogen atom during the above-described reactions. Hydrogen-donating solvents are distinguishable from hydrogen-containing solvents, such as benzene, 1-chloro-naphthalene and 1-chlorobenzene, which do not possess a hydrogen, which may be donated during the reaction mechanism of the present invention. Suitable hydrogen-donating solvents for use in the present invention may vary according to the reactants, reaction temperature, and other reaction parameters. Suitable hydrogen-donating solvents include, but are not limited to, substituted aromatic compounds; cyclohexadiene; alcohols, such as 2-propanol; ethers, such as petroleum ether, tetrahydrofuran, dioxane, and tetralene. Desirably, the solvent comprises o-xylene, m-xylene, p-xylene, toluene, or a substituted benzene, wherein the substituent comprises a hydrogen-containing moiety. More desirably, the solvent comprises p-xylene, toluene, or cumene. Even more desirably, the solvent comprises p-xylene or cumene.
The methods of the present invention produce a variety of subphthalocyanine compounds at yields of greater than about 50%. Desirably, the method of making subphthalocyanine compounds has a yield of greater than about 60%. More desirably, the method of making subphthalocyanine compounds has a yield of greater than about 70%. Even more desirably, the method of making subphthalocyanine compounds has a yield of greater than about 80%. Even more desirably, the method of making subphthalocyanine compounds has a yield of greater than about 85%. Even more desirably, the method of making subphthalocyanine compounds has a yield of greater than about 90%. Most desirably, the method of making subphthalocyanine compounds has a yield of greater than about 94%.
In the methods of the present invention, one or more reactants may be used in combination with one or more hydrogen-donating solvents. Suitable reactants include, but are not limited to, phthalonitrile, one or more substituted phthalonitriles, pyridine-2,3-dicarbonitrile, one or more substituted pyridine-2,3-dicarbonitriles, pyridine-3,4-dicarbonitrile, one or more substituted pyridine-3,4-dicarbonitriles, pyrazine-2,3-dicarbonitrile, one or more substituted pyrazine-2,3-dicarbonitriles, or a combination thereof. Substituted phthalonitrile compounds include phthalonitrile compounds having up to six moieties bonded to the aromatic ring of the phthalonitrile compound. Further, substituted pyridine-2,3-dicarbonitrile compounds include pyridine-2,3-dicarbonitrile compounds having up to three additional moieties bonded to the aromatic ring of the pyridine-2,3-dicarbonitrile compound. Substituted pyridine-3,4-dicarbonitrile compounds include pyridine-3,4-dicarbonitrile compounds having up to three additional moieties bonded to the aromatic ring of the pyridine-3,4-dicarbonitrile compound. Substituted pyrazine-2,3-dicarbonitrile compounds include pyrazine-2,3-dicarbonitrile compounds having up to two additional moieties bonded to the aromatic ring of the pyrazine-2,3-dicarbonitrile compound.
Suitable moieties on the above-referenced substituted reactants include, but are not limited to, halogens, alkyl groups, alkoxy groups, cyano groups, carboxylic acid groups, sulfur-containing groups, nitrogen-containing groups, and salts thereof. Suitable halogens include, but are not limited to, chlorine, bromine, fluorine, and iodine. Suitable alkyl groups include, but are not limited to, methyl groups, ethyl groups, and tert-butyl groups. Suitable alkoxy groups include, but are not limited to, methoxy groups and ethoxy groups. Suitable sulfur-containing groups include, but are not limited to, xe2x80x94SC8H17, xe2x80x94SO3H, xe2x80x94SO3Na, -SO3Cl, and xe2x80x94SO3Clxe2x88x92. Suitable nitrogen-containing groups include, but are not limited to, xe2x80x94NO2, xe2x80x94pyH+, xe2x80x94NR2, and xe2x80x94NR3, wherein R represents xe2x80x94H, a halogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an alkoxide group, a phenoxy group, a substituted phenoxy group, an alkyl sulfide, an aryl sulfide, a nitrogen-containing group, a sulfonic acid, a sulfur-containing group, or an ester group. Other suitable groups also include, but are not limited to, xe2x80x94CO2Na.
In addition to the above reactants, one or more boron-containing compounds may be used in the methods of the present invention. Suitable boron-containing compounds include, but are not limited to, halogen-substituted boron compounds, such as boron trichloride, boron trifluoride, and boron tribromide. Other suitable boron-containing compounds include mixed boron compounds containing at least one halogen atom and at least one phenyl group. Such mixed boron compounds include, but are not limited to, BCl2Ph, BClPh2, BBr2Ph, and BBrPh2, wherein xe2x80x9cPhxe2x80x9d represents a phenyl group.
In one embodiment of the present invention, subphthalocyanine compounds are produced using the reaction mechanism described below: 
In step 1, X represents any Lewis base. Desirably, X is a halogen. More desirably, X is Cl. 
In step 9 two electrons are donated from hydrogen atoms of the hydrogen-donating solvent. The interaction of hydrogen atoms in the above mechanism may be described below: 
The hydrogen-donating solvent supplies two hydrogen atoms, which form two hydrogen ions and two electrons. The electrons balance the charge on two nitrogen atoms in the subphthalocyanine compound. The two hydrogen ions react with the Lewis base released by the boron compound to form two acid molecules as shown below. 
In a further embodiment of the present invention, subphthalocyanine compounds are produced using the following reaction mechanism. Steps 1-4 are the same steps as described above. Steps 5-11 are described below: 
In the above mechanisms, although phthalonitrile is shown as the reactant in Steps 1, 2, and 5 (of the first mechanism), it is to be understood that one or more unsubstituted phthalonitriles, substituted phthalonitriles, unsubstituted pyridine-2,3-dicarbonitriles, substituted pyridine-2,3-dicarbonitriles, unsubstituted pyridine-3,4-dicarbonitriles, substituted pyridine-3,4-dicarbonitriles, or a combination thereof may be used in Steps 1, 2, and 5 of the reaction mechanisms described above. Further, as shown in the second mechanism, a xe2x80x9ccappedxe2x80x9d phthalonitrile may be used as a reactant. In this embodiment, the capped phthalonitrile may be formed by the following reaction: 
As in the first mechanism, the hydrogen-donating solvent supplies two electrons from hydrogen atoms in the solvent as shown in Step 11.
The present invention is further directed to a new family of subphthalocyanine compounds having the following general formula: 
wherein X1 to X12 each independently represent carbon or nitrogen; R1 to R12 and Z each independently represent xe2x80x94H; a halogen; an alkyl group containing up to about 12 carbon atoms; a substituted alkyl group containing up to about 18 carbon atoms along the alkyl backbone; an aryl group; a substituted aryl group; an alkoxide group containing up to about 12 carbon atoms; a phenoxy group; a substituted phenoxy group; an alkyl sulfide containing up to about 8 carbon atoms; an aryl sulfide; a nitrogen-containing group; a sulfonic acid; a sulfur-containing group; a lanthanide-containing group; xe2x80x94ORxe2x80x2, xe2x80x94NRxe2x80x3Rxe2x80x3, or xe2x80x94SRxe2x80x2, wherein Rxe2x80x2 and Rxe2x80x3 each independently represent an alkyl group containing up to about 8 carbon atoms, a substituted alkyl group containing up to about 12 carbon atoms along the alkyl backbone, an aryl group, or a substituted aryl group; and wherein when any one of X1 to X12 is nitrogen, the corresponding R1 to R12 represents the pair of electrons on the nitrogen atom. Desirably, R1 to R12 each independently represent xe2x80x94H, a halogen, an alkyl group containing up to about 8 carbon atoms, a nitrogen-containing group, a sulfur-containing group, or a lanthanide-containing group. More desirably, R1 to R12 each independently represent xe2x80x94H, chlorine, bromine, fluorine, iodine, a tert-butyl group, xe2x80x94NO2, xe2x80x94SC8H17, xe2x80x94SO3H, xe2x80x94SO3Na, xe2x80x94SO2Cl, xe2x80x94SO3xe2x88x92p y H+, or a Eu-containing moiety. Even more desirably, R1 to R12 each independently represent xe2x80x94H, chlorine, bromine, fluorine, or iodine.
Suitable Z substituents may be selected from a variety of substituents, which provide desirable properties to the resulting subphthalocyanine compound. Desirably, Z comprises a moiety, which stabilizes the subphthalocyanine compound; a moiety, which renders the subphthalocyanine compound water soluble; or a moiety, which stabilizes and renders the subphthalocyanine water soluble. Examples of suitable Z include, but are not limited to, a hydroxyl group; a halogen; an alkyl group containing up to about 12 carbon atoms; an alkoxy group containing up to about 12 carbon atoms; an ether group; a polyol group; an aromatic group; a substitute aromatic group; a nitrogen-containing group; a sulfur-containing group; a lanthanide-containing group; xe2x80x94ORxe2x80x2, xe2x80x94NRxe2x80x2Rxe2x80x3, or xe2x80x94SRxe2x80x2, wherein R and Rxe2x80x3 each independently represent an alkyl group containing up to about 8 carbon atoms, a substituted alkyl group containing up to about 8 carbon atoms, an aryl group, or a substituted aryl group. Desirably, Z comprises one of the following moieties: 
where x is an integer from 3 to 30, y is from 0 to 6, Rxe2x80x2xe2x80x3 is a hydrogen or an alkyl group having up to six carbon atoms, and L is acetate; halogens; ethylene diamine; compounds having the following structure, H2N(CH2)xNH2, wherein x is from 2 to 8; propionate; nitrate; or oxalate.
By selecting particular xe2x80x9cRxe2x80x9d and xe2x80x9cZxe2x80x9d groups, subphthalocyanine compounds having superior lightfastness properties may be produced. In one embodiment of the present invention, subphthalocyanine compounds having superior lightfastness properties are produced; these compounds have the above general formula, wherein X1 to X12 each independently represent carbon or nitrogen; R1 to R12 each independently represent xe2x80x94H, a halogen, or xe2x80x94SRxe2x80x2; and Z represents a halogen, an aryl group, a substituted aryl group, a pyridine group, a substituted pyridine group,xe2x80x94ORxe2x80x2, xe2x80x94NRxe2x80x2Rxe2x80x3, or xe2x80x94SRxe2x80x2, wherein Rxe2x80x2 and Rxe2x80x3 each independently represent an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group.
In a further embodiment of the present invention, subphthalocyanine compounds having the above general formula are produced, wherein X1 to X12 each independently represent carbon or nitrogen; R1 to R12 each independently represent xe2x80x94H, a halogen, or xe2x80x94SRxe2x80x2; and Z is desirably a phenyl group, an aryl group, or a substituted aryl group. In this embodiment, the phenyl group, aryl group, or substituted aryl group prevents a photochemical 1,3 shift of the axial ligand as shown in the example mechanism below: 
The superior lightfastness property of a given subphthalocyanine compound may be measured by the xe2x80x9cSubphth.-Lightfastness Testxe2x80x9d described herein. The Subphth.-Lightfastness Test used in the present invention measures the percent change in absorption of a 5xc3x9710xe2x88x925 M concentration solution of the subphthalocyanine compound in o-xylene, and is given by the following equation:
xe2x80x83%xcex94A=[(P0xe2x88x92P144)/P0]xc3x97100
wherein P0 represents an absorption value at time zero (i.e., at the start of the test) and P144 represents an absorption value after 144 hours of exposure to a standard fluorescent lamp (i.e., Sylvania Cool White, 115 W, Model No. F48T12) placed about six feet from the subphthalocyanine compound. Desirably, the subphthalocyanine compound of the present invention has a Subphth.-Lightfastness Test value of less than about 15%. More desirably, the subphthalocyanine compound of the present invention has a Subphth.-Lightfastness Test value of less than about 12%. Even more desirably, the subphthalocyanine compound of the present invention has a Subphth.-Lightfastness Test value of less than about 10%.
As shown by the general formula above, the present invention is directed to a number of new subphthalocyanine compounds. Subphthalocyanine compounds of the present invention include, but are not limited to, the following compounds given below, wherein 
and wherein R1-4 represents R1 to R4, R5-8 represents R5 to R8, and R9-12 represents R9 to R12: 
It is believed that the new subphthalocyanine compounds of the present invention possess superior lightfastness properties due to their reduced time in the excited state, as well as, their lower probability of being in the excited state. The presence of one or more substituents having high xe2x80x9cZxe2x80x9d values (i.e., atomic number) on the aromatic rings of the compounds produces a xe2x80x9cheavy atom effect,xe2x80x9d also known as xe2x80x9cspin orbital coupling,xe2x80x9d which enables the distribution of vibrational energy at an excited state, resulting from exposure to light, intramolecularly. This xe2x80x9cintramolecular quenchingxe2x80x9d of the molecule results in rapid quenching of the excited state back to the ground state. The net effect being a much smaller concentration of excited state species at any one time. A general discussion of xe2x80x9cheavy atom effectxe2x80x9d and xe2x80x9cspin orbital couplingxe2x80x9d may be found in the Handbook of Photochemistry (Murov et al.), 2nd ed., Section 16, entitled xe2x80x9cSpin-Orbit Couplingxe2x80x9d, pages 338-341 (1993), the entirety of which is incorporated herein by reference.
In one embodiment of the present invention, subphthalocyanine compounds having superior lightfastness are formed, wherein one or more xe2x80x9cRxe2x80x9d and/or xe2x80x9cZxe2x80x9d groups have a spin-orbital coupling constant, "igr"l, of greater than about 500. Suitable xe2x80x9cRxe2x80x9d and/or xe2x80x9cZxe2x80x9d groups have a spin-orbital coupling constant of greater than about 500 include, but are not limited to, chlorine ("igr"l=587), europium ("igr"l=1469), bromine ("igr"l=2460), and iodine ("igr"l=5069). Desirably, the subphthalocyanine compounds of the present invention contain one or more xe2x80x9cRxe2x80x9d and/or xe2x80x9cZxe2x80x9d groups, which have a spin-orbital coupling constant, "igr"l, of greater than about 500. More desirably, the subphthalocyanine compounds of the present invention contain one or more xe2x80x9cRxe2x80x9d and/or xe2x80x9cZxe2x80x9d groups, which have a spin-orbital coupling constant, "igr"l, of greater than about 1000. Even more desirably, the subphthalocyanine compounds of the present invention contain one or more xe2x80x9cRxe2x80x9d and/or xe2x80x9cZxe2x80x9d groups, which have a spin-orbital coupling constant, "igr"l, of greater than about 1400.
As discussed above, it is believed that adding one or more substituents having high xe2x80x9cZxe2x80x9d values (i.e., atomic number) onto the aromatic rings of the subphthalocyanine compounds produces xe2x80x9cintramolecular quenchingxe2x80x9d of the molecule. In addition to xe2x80x9cintramolecular quenchingxe2x80x9d of the subphthalocyanine compound, xe2x80x9cintermolecular quenchingxe2x80x9d of the subphthalocyanine compound may be accomplished by associating one or more quenching compounds with the subphthalocyanine compound. An example of xe2x80x9cintermolecular quenchingxe2x80x9d is shown in the structure below: 
wherein a copper compound forms a coordinate covalent bond with two pair of electrons present on nitrogen atoms in close proximity to one another within the subphthalocyanine compound. A further example of xe2x80x9cintermolecular quenchingxe2x80x9d is shown in the subphthalocyanine complex below: 
wherein a copper compound forms a coordinate covalent bond with two pair of electrons present on nitrogen atoms in close proximity to one another within the subphthalocyanine compound. In the Cu(L)2 compound, xe2x80x9cLxe2x80x9d may be any moiety capable of complexing with the copper atom. Suitable xe2x80x9cLxe2x80x9d moieties include, but are not limited to, acetate; halogens; ethylene diamine; and compounds having the following structure, H2N(CH2)xNH2, wherein x is from 2 to 8; propionate; nitrate; and oxalate. It should be noted that compounds other than Cu(L)2 may be used as a quenching moiety. Other compounds include, but are not limited to, other complexing transition metals and compounds containing a transition metal.
The above-described subphthalocyanine compound-containing complexes having xe2x80x9cintramolecular quenchingxe2x80x9d and xe2x80x9cintermolecular quenchingxe2x80x9d may be formed by reacting a subphthalocyanine compound with one or more complexing transition metals and compounds containing a transition metal. One method of reacting the above-described subphthalocyanine compounds with the quenching moiety is to simply mix the materials, add the mixture to a solvent, and allow the mixture to react at room temperature. Suitable solvents include, but are not limited to, dimethyl sulfoxide and dimethyl formamide. In some cases, the reaction may take place at a reaction temperature of up to about 100xc2x0 C.
A variety of subphthalocyanine compound-containing complexes may be formed by the above-described reaction mechanism. By selecting particular xe2x80x9cRxe2x80x9d groups, axial ligand Z, and quenching groups, subphthalocyanine compound-containing complexes having superior lightfastness properties may be produced. Examples of possible subphthalocyanine compound-containing complexes include, but are not limited to, 
Other desired subphthalocyanine compound-containing complexes include, but are not limited to, the above compounds wherein the axial ligand comprises a substituted aryl having the formula 
wherein R31 to R35 each independently represent xe2x80x94H, a halogen, xe2x80x94NO2, a carboxy group, or a carbonyl group.
One example of a subphthalocyanine compound-containing complexes wherein the axial ligand contains a quenching compound is given below. 
It should be noted that the above compound is only one example of many subphthalocyanine compound-containing complexes of the present invention, wherein the axial ligand contains a quenching compound.
In a further embodiment of the present invention, two subphthalocyanine compounds are reacted with a third reactant to obtain a compound having the following general formula: 
wherein R21, to R36, Z1, and Z2 each independently represent moieties as described above with respect to R1 to R12 and Z. In the formation of the above compound, the third reactant may be selected from 1,3,4,6-tetracyanobenzene or 1,3,4,6-tetracyanobenzene further substituted with one or more electron-withdrawing groups, E1 and E2. Suitable electron-withdrawing groups xe2x80x9cExe2x80x9d include, but are not limited to, a halogen; xe2x80x94NO2, a halogen, xe2x80x94ORxe2x80x2, and xe2x80x94CO2Rxe2x80x2, wherein Rxe2x80x2 represents an alkyl group containing up to about 8 carbon atoms, a substituted alkyl group containing up to about 12 carbon atoms along the alkyl backbone, an aryl group, or a substituted aryl group.
The above-described subphthalocyanine compounds may be used as a colorant, alone or in combination with one or more other colorants. The subphthalocyanine compounds may be incorporated into ink compositions, which may form an ink set including yellow, blue, black, and magenta inks.
The present invention also relates to colorant compositions having improved stability, wherein the colorant comprises one or more of the above-described subphthalocyanine compounds. Desirably, one or more of the new subphthalocyanine compounds are admixed with or covalently bonded to a colorant stabilizer. The colorant stabilizer may be one or more colorant stabilizers disclosed in the following U.S. patent applications Ser. Nos. 08/563,381 filed Nov. 28, 1995, now abandoned; Ser. No. 08/589,321 filed Jan. 22, 1996, now abandoned; and Ser. No. 08/788,863 filed Jan. 23, 1997, pending; and U.S. Pat. Nos. 5,782,963; 5,855,655; 5,885,337; and 5,891,229; all of which are assigned to Kimberly Clark Worldwide, Inc., the entirety of which is incorporated herein by reference. Optionally, the new subphthalocyanine compounds may be associated with a molecular includant, chelating agent, or other material to improve solubility and/or interaction of the subphthalocyanine compound and any colorant stabilizers present. Suitable molecular includant, chelating agent, and other composition materials are also disclosed in the above-referenced U.S. Patent Applications and Patents assigned to Kimberly Clark Worldwide, Inc., the entirety of which is incorporated herein by reference.
In one embodiment of the present invention, the above-described subphthalocyanine compound is covalently bonded to a colorant stabilizer in the form of a porphine. Suitable porphines are disclosed in U.S. Pat. Nos. 5,782,963; 5,855,655; and 5,891,229; all of which are assigned to Kimberly Clark Worldwide, Inc., the entirety of which is incorporated herein by reference. Desirably, the porphine is covalently bonded to the subphthalocyanine compound at Z, Z1, and/or Z2. In a further embodiment of the present invention, two subphthalocyanine compounds are covalently bonded to one another. In this embodiment, it is desirable for one subphthalocyanine compound to be bonded to the other subphthalocyanine compound at Z, Z1 and/or Z2.